SAS3 Backplaine and HBA Upgrade

Discussion in 'RAID Controllers and Host Bus Adapters' started by avsion, Aug 6, 2019.

  1. BLinux

    BLinux cat lover server enthusiast

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    There is actually one other difference that I can think of, and that is the LED behavior. Granted, not a functional problem and more cosmetic, but it might really bug people who are a bit OCD, especially if mixing SAS/SATA drives.

    we've discussed this in some other threads so i'll just link here:

    https://forums.servethehome.com/ind...haviors-differ-with-sas-vs-sata-drives.19042/
     
    #21
  2. avsion

    avsion New Member

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    @i386 OK will try to explain bit different

    Direct connection = Option 1 & 3
    Expender = Option 2
    Point of Failure = Cable, ports on the BPN, Port on the HBA
    Link - Connection between the HBA and the backplane

    Option 2 in my OP has one link between the two devices, option 1 and 3 has total 6 links between the two devices. if the link in option 2 goes down all 24 drives will be down, however if in option 1 or 3 one link goes down only 4 drives will be disconnected however the rest of the 20 drives from link 1-5 will be active. 1-1 = 0 or 6 - 1 = 5 you can call it failover, reliable, redundancy or some kind of backup.

    EL2
    From Supermicro prospective the second expender is mainly designed for failover purposes, if the first Chip/HBA goes down the second one takes over.

    From the manual
    - The SAS-836EL2 backplane has two expanders which allow effective failover and recovery.
    - Primary and Secondary Expander Chips - This primary and secondary expander chips allow the backplane to support dual ports, cascading, and failover.

    hope it make more sense now
     
    #22
  3. i386

    i386 Well-Known Member

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    I think that's not correct: the second expander is connected to the second sas port on the hdd/ssd; the axpander doesn't know that there is another expander on the backplane.
    If the first path fails (expander 1 or hba 1 is dead) the storage devices can still be accessed through the second path (expander 2 <-> hba 2)
    Does it matter for the logical volume if all devices are not available or multiple mirror pairs?
     
    #23
  4. kapone

    kapone Active Member

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    @avsion - Your choice of a "direct attached" (A or TQ) backplane vs an expander based backplane (EL1/EL2) should be dictated by how much bandwidth you need from your disks, not "failover, reliable, redundancy or some kind of backup".

    Bandwidth is the only driver that matters in this case.
     
    #24
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  5. avsion

    avsion New Member

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    yes if i have one out of the six VMs is down is better then all 6 down
     
    #25
  6. avsion

    avsion New Member

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    Hi Guys,

    Just an update, i end up getting the LSI 9305 - 24i HBA with 6 SM mini SAS to SATA cables, using my TQ backplane. replaces 2 of the PWS-902-1R with PWS-920p-SQ. got 10 x 2.5" tray for the ssd's. replaced all stock fans inc fan chassis (custom made fan support) with noctua 3 120mm for the HDD and 2 80mm for the exhaust. i used STUX script for controlling all the fans 2 zones CPU and HDD. as i didn't want to use the SATA Cables that was connected to the MB SATA ports (ESXi VMs ssds), but use an HBA, i flashed my LSI 9300-8i from IT to IR so now all using the SM cables with the HBA. and finally completed with cabling management. the system is back online working as expected very happy. now need to investigate how to test the bandwidth. see attached pictures

    Thank you for everyone help much appreciated :)


    4AHBK2cvQK+5LKpW2Ad%lw.jpg 8RJGR0DdQXejY+YsSjiHWA.jpg HTVsNuNoSa2DqEUNAj7ISA.jpg OHi8ScfzRv6n8znXqf5vQQ.jpg
     
    #26
    Last edited: Aug 15, 2019
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  7. ari2asem

    ari2asem Member

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    ;)nice cable management
     
    #27
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  8. avsion

    avsion New Member

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    Thank you its called the AU Python CM :D
     
    #28
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